1. Field of the Invention
This invention relates to chain printers and, more particularly, to an improved type belt for a chain printer.
2. Prior Art
The prior art to which this invention is directed teaches an arrangement for the type belt for a chain printer in which the print slug is fixed to the timing belt by means of pins mounted into extensions of the print slug and elongated coil springs. These are disclosed by U.S. Pat. Nos. 3,621,778 and 3,633,500. However, the above described system has some disadvantages. First, it consumes a considerable amount of time in mounting and demounting the print slugs from the timing belt, and in addition a greater number of parts are required. Another disadvantage of the prior art is the manufacturing complexity. That is, the system necessitates an intricate configuration of parts in order for the timing belt to gear properly with the driving pulley. In the case of U.S. Pat. No. 3,633,500, the shape of the driving pulley must be so designed as to avoid the interference between the driving pulley and the elongated coil springs, while in the case of U.S. Pat. No. 3,621,778, the pin mounted onto the extension of the printing slug is divided into upper and lower parts to protect it from interference between the pin and the printing slug. Accordingly, a longer time is spent in the manufacturing process of the devices described above. In addition, the arrangement in which the timing belt engages the driving pulley is likely to cause wear and tear of the timing belt after some period of operation. This will result in the deterioration of the printing performance of the device.
This invention solves these problems which the prior art devices described above have failed to solve.